IMO the main things to consider are the AF abilities (I don't use tracking and I don't need lightening speed so mirrorless and it's highly accurate if less speedy than the very fastest DSLR's focusing is adequate for me,) bulk, weight and the EVF v OVF question.
I jumped to mirrorless for the smaller form factor and now also greatly appreciate the benefits of the EVF system with its in view aids and WYSIWYG. I also value the ability to use and focus easily and accurately with old manual lenses.
I went mirrorless years ago and I wouldn't go back to DSLR's. My keeper rate has never been higher and I no longer need to guess what the final image will look like and chimp quite so often
It's a different way of shooting and it may not be for everyone, the kit can be on the expensive side when compared to DSLR's too.